2024-11-23

file backup

Data Backup Terminology

DATARECOVERYUNION.COM012 mins

Data Backup Terminologybackup policy
an organisation’s procedures and rules for ensuring that adequate amounts and types of backups are made, including suitably frequent testing of the process for restoring the original production system from the backup copies.

backup rotation scheme
a method for effectively backing up data where multiple media are systematically moved from storage to usage in the backup process and back to storage. There are several different schemes. Each takes a different approach to balance the need for a long retention period with frequently backing up changes. Some schemes are more complicated than others.

backup site
a place where business can continue after a data loss event. Such a site may have ready access to the backups or possibly even a continuously updated mirror.

backup software
computer software applications that are used for performing the backing up of data, i.e., the systematic generation of backup copies.

backup window
the period of time that a system is available to perform a backup procedure. Backup procedures can have detrimental effects to system and network performance, sometimes requiring the primary use of the system to be suspended. These effects can be mitigated by arranging a backup window with the users or owners of the system(s).

copy backup
backs up the selected files, but does not mark the files as backed up (reset the archive bit). This is found in the backup with Windows 2003.

cumulative incremental backup
a differential backup used by NetBackup.

daily backup
incremental backup used by Windows Server 2003.

data salvage
the process of recovering data from storage devices when the normal operational methods are impossible. This process is typically performed by specialists in controlled environments with special tools. For example, a crashed hard disk may still have data on it even though it doesn’t work properly. A data salvage specialist might be able to recover much of the original data by opening it up in a clean room and tinkering with the internal parts.

differential backup
a cumulative backup of all changes made since the last full backup. The advantage to this is the quicker recovery time, requiring only a full backup and the latest differential backup to restore the system. The disadvantage is that for each day elapsed since the last full backup, more data needs to be backed up, especially if a majority of the data has been changed.

differential incremental backup
an incremental backup used by NetBackup.

disaster recovery
the process of recovering after a business disaster and restoring or recreating data. One of the main purposes of creating backups is to facilitate a successful disaster recovery. For maximum effectiveness, this process should be planned in advance and audited.

disk image
a method of backing up a whole disk or filesystem in a single image. Since the underlying data structures are what is actually backed up, this method does not allow for file level control over what is selected for backup or restore.

FlashBackup
a term used for raw partition backup used by NetBackup Advanced Client. In NBAC, support is limited to the VxFS (Veritas), ufs (Solaris), Online JFS (HP-UX), and NTFS (Windows) filesystem types. Similar to the UNIX utility dump.

full backup
a backup of all (selected) files on the system. In contrast to a drive image, this does not included the file allocation tables, partition structure and boot sectors.

hot backup
a backup of a database that is still running, and so changes may be made to the data while it is being backed up. Some database engines keep a record of all entries changed, including the complete new value. This can be used to resolve changes made during the backup.

incremental backup
a backup that only contains the files that have changed since the most recent backup (either full or incremental). The advantage of this is quicker backup times, as only changed files need to be saved. The disadvantage is longer recovery times, as the latest full backup, and all incremental backups up to the date of data loss need to be restored.

media spanning
sometimes a backup job is larger than a single destination storage medium. In this case, the job must be broken up into fragments that can be distributed across multiple storage media.

multiplexing
the practice of combining multiple backup data streams into a single stream that can be written to a single storage device. For example, backing up 4 PCs to a single tape drive at once.

multistreaming
the practice of creating multiple backup data streams from a single system to multiple storage devices. For example, backing up a single database to 4 tape drives at once.

normal backup
full backup used by Windows Server 2003.

near store
provisionally backing up data to a local staging backup device, possibly for later archival backup to a remote store device.

open file backup
the ability to back up a file while it is in use by another application. See File locking.

remote store
backing up data to an offsite permanent backup facility, either directly from the live data source or else from an intermediate near store device.

restore time
the amount of time required to bring a desired data set back from the backup media.

retention time
the amount of time in which a given set of data will remain available for restore. Some backup products rely on daily copies of data and measure retention in terms of days. Others retain a number of copies of data changes regardless of the amount of time.

site-to-site backup
backup, over the internet, to an offsite location under the user’s control. Similar to remote backup except that the owner of the data maintains control of the storage location.

synthetic backup
a term used by NetBackup for a restorable backup image that is synthesized on the backup server from a previous full backup and all the incremental backups since then. It is equivalent to what a full backup would be if it were taken at the time of the last incremental backup.

tape library
a storage device which contains tape drives, slots to hold tape cartridges, a barcode reader to identify tape cartridges and an automated method for physically moving tapes within the device. These devices can store immense amounts of data.

true image restore
a term used by NetBackup and Backup Exec for the collection of file deletion and file movement records so that an accurate restore can be performed. For instance, consider a system that has a directory with 5 documents in it on Friday. On Saturday, the system gets a full backup that includes those 5 documents. On Monday, the owner of those documents deletes 2 of them and updates 1 of the 3 remaining. That updated document gets backed up as part of The Monday night incremental backup. On Tuesday afternoon the system crashes. If we perform a normal restore of the full backup from Saturday and the incremental backup from Monday to the fresh system, we will have restored the 2 documents that were intentionally deleted. True image restore keeps track of the deletions with each incremental backup and prevents the deleted files from being inappropriately restored.

trusted paper key
a machine-readable print of a cryptographic key.

virtual Tape Library (VTL)
a storage device that appears to be a tape library to backup software, but actually stores data by some other means. A VTL can be configured as a temporary storage location before data is actually sent to real tapes or it can be the final storage location itself.

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Free Remote File Storage/Sharing/Backup

DATARECOVERYUNION.COM42 mins

The services listed in this section enable you to backup, store and/or share your files on the Internet for free.

4shared.com
1 Gigabyte of free space to share files.

DriveHQ
Free 1Gb of remote storage space including FTP access and file-sharing. The non-free plans range from 2 Gb for $ 2.99/month up to 20 Gigabytes for $19.99/Month

File Hamster
Free real-time backup and archiving of your files while you work, monitor specific files on your hard drive and automatically create incremental backups, etc.

FLASHspace
Remote storage space which presents itself as simply another disk-drive inside your Windows computer (no software needs to be installed).The 50 Mb package is free. The non-free packages start from $ 2 per month for 500 Mb.

Huddle
1GB of free file storage space.

I(2) Drive
500 Mb storage, 1 Gb transfer for $ 9.99 per month

Internet Virtual Storage
A list of sites providing internet based storage solutions, i.e. remote virtual hard drives or remote virtual storage space, both free and commercial.

myDataBus
5 Gigabytes of free file storage, maximum file size: 500 Mb.

Orbitfiles
6 Gigabytes of free online file storage, backup and file-sharing.

Sharemation
5 Mb of free file storage.

Webdrive.dk
100 MB free space, share folders with other users, access zip files online.

Xdrive
Non-free, 15 day free trial. Integrates with the Windows explorer as an extra drive. 5 Gb secure storage for $9.95 per month; 25 Gb Xdrive work-group storage for $ 99.95 per month.

Yahoo Briefcase
30 Mb of free files storage. Save Yahoo! Mail attachments directly to your Yahoo! Briefcase.

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Free system backup softwares

DATARECOVERYUNION.COM01 mins

Freebyte Backup
Freebyte Backup is a very effective freeware backup program for Windows. It enables you to easily backup files from any amount of directories and sub-directories.

Freebyte Backup can backup all files, or a selection of files: you can filter according to file-date, file-type and even perform an incremental backup. Also: support for profiles.Small, simple to use, and simple to install (no dll’s!!).

Easeus Disk Copy
Free program which can create an exact (Mirror Image, Disk to Disk) copy of your old disk, including the operating system, applications, personal preferences, custom settings, data, lost files, and inaccessible data. It can be used for backup, cloning, your original small hard drive to a new larger drive.

TreePad X Enterprise
384 Gigabyte Personal Information Manager and Word Processor.Intuitive and versatile, including Website Generator, spellchecker, thesaurus, attachments, search engine, recycle bin, and much more!

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The Ever Growing Challenges of Data Storage

DATARECOVERYUNION.COM011 mins

Electronic data storage needs continue to grow. As your client’s organization produces more information in electronic format, storage space is becoming increasingly important.

Managing data storage for performance, integrity, and scalability is the next summit in Information Technology management and planning.

It wasn’t long ago that having a single volume in the terabyte size range was rare for extremely large organizations. With the advent of IDE RAID and SATA RAID capabilities, large storage systems are within reach of medium to small businesses.

Let’s put things into perspective – how much space is 1TB?

Number of Bytes

What that relates to

1 Byte

One character (letter or number)

1KB (Kilobyte) 1000 bytes

3 or 4 typed manuscript style pages

1MB (Megabyte) 1,000,000 bytes

Average size of a novel (300-400pgs); 1 diskette

1GB (Gigabyte) 1,000,000,000 bytes

Approximately 20 sets of encyclopedias

1TB (Terabyte) 1,000,000,000,000 bytes

A small library (approx. 5,000 books)

Number of Bytes What that relates to

To get the best performance and reliability from any storage space, strategic storage planning is essential. This month’s technical article will review the importance of the file system and planning considerations.
The File System’s Role

The file system’s role is a layer above the storage device(s) itself. The file system manages the individual allocation units of the volume and provides hierarchical organization for the files. Managing the allocation units of the files requires algorithms that will know where to write file data and have a method of verifying that the data was written correctly.

Hierarchical organization is the logical formation of directories and underlying structures. For instance, a storage volume that has millions of files on it will have specific data that describes the directory or folder structure of where these files belong. This directory or folder structure has integrity checks and balances to ensure that the indices reliably point to the user data.

Today’s file systems track more than just the name of the file or directory structure. Additional information called Metadata is also stored. Metadata is data about data. Essentially, the file system is saving more details about your files and is storing this along with attributes of the file. Some file systems record only the minimum of metadata (file name, size, time and date, start address), while other file systems record more information (file name, size, multiple time and dates, security details such as Read/Write/Execute/Delete privileges).

Some file systems are designed for specific hardware and storage media. For instance, the file systems used for CD-ROMs are quite different than those for floppy diskettes. Forcing these file systems on other media may be possible, but not practical. So while specific storage media, such as CD-ROM, DVD-ROM, magnetic-optical disks, and tape, have unique file systems, hard disk and hard disk storage systems can work with many different file systems.

Understanding these extra features of file systems will help in choosing the best one for the needs of the volume.

File System Considerations

During server planning, more time and research is spent on hardware, data space requirements, and application specifications than on how the data will be stored. The file system can become a low priority during the planning stages of a file or data server because the file system is inherent to the operating system. Sometimes it is assumed that this is best fit. However, your storage requirements may call for a more robust method of data organization on the hard disk(s). Investigate whether the operating system you are planning to use allows the other file systems to be used.

If you have a choice of file systems, here are some requirements to consider:

• Volume Size
• Estimated number of files on the volume
• Estimated size of files on the volume
• Shared volume requirements
• Backup Requirements

Volume Size

Volume size is an important place to start for planning. However, this is only the start since strategic planning involves scalability—can it grow as the need arises without interruption of service to the users? The axiom of filling free space is all too true for data volumes. It is not uncommon to add a terabyte of storage and in six months it’s already half full.

Two terabytes (2TB) has become the initial hurdle for many file systems. This limit starts with the SCSI command set being limited to 32-bit logical block addressing. Therefore, a single SCSI LUN using 512 byte block size cannot access over 2TB. File systems that have been used on these systems have been ‘adjusted’ to handle extremely large volumes. However, volumes that are nearing the 2TB limit may be stressing the limits of the file system.

Estimated Number of Files on the Volume

The next item to plan for is the number of files that could potentially be stored on the volume. Earlier we discussed Metadata and how the file system uses this to describe the files that are stored. This means there is going to be a certain amount of volume space used by the file system just to manage the files that are there.

File systems that are not built for excessively large directories will slow down applications that access them. This can adversely affect users that have thousands of files on a volume that has millions of files.
Estimated Size of Files on the Volume

The next consideration is the sizes of the files that will be on the volume. Organizations that are running large database servers usually have the need to be able to pre-allocate very large files in the gigabyte range of sizes. The file system and operating system need to be able to handle this level of input and output. For these types of enterprises’ systems, expectations are high for performance and integrity. Will the file system be able to handle those extremely large files?

Shared Volume Requirements

There are mixed environments in many organizations today. Some organizations may have three or four different platforms of computer systems; from mainframe systems to 64-bit Sun machines, from Apple desktops to Intel based machines. Some of these systems may share storage space. Will the volume support mixed data types? Additionally, will the operating system that manages the file system allow for different types of data streams to be accessed simultaneously?
Backup Requirements

Large volumes present a challenge for backup procedures. Due to the amount of data, restorations can take days. There are some file systems that have ‘Snap-shot’ technology incorporated into the backup software. This technology saves critical file system metadata. This, along with incremental file backups, is part of entire system scheme of data archiving.

These considerations should be matched with hardware specifications to get the best performance, integrity, and growth capability.

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